Failure processing method, handover method, terminal device, and network device

ABSTRACT

This application provides failure processing methods, handover methods, terminal devices, and network devices. One method includes receiving a radio resource control (RRC) configuration of a secondary network device, if the RRC configuration of the secondary network device is from the secondary network device and the RRC configuration fails, sending, to a primary network device, first indication information for indicating a configuration failure of the RRC configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/573,465, filed on Sep. 17, 2019, which is a continuation ofInternational Application No. PCT/CN2018/085710, filed on May 4, 2018,which claims priority to Chinese Patent Application No. 201710314196.5,filed on May 5, 2017. All of the afore-mentioned patent applications arehereby incorporated by reference in their entireties.

TECHNICAL FIELD

This application relates to the field of wireless communicationtechnologies, and in particular, to a failure processing method, ahandover method, a terminal device, and a network device in a wirelesscommunications system.

BACKGROUND

FIG. 1 shows a multi-connectivity scenario. One terminal device isconnected to one primary network device and at least one secondarynetwork device (one secondary network device is used as an example inthe figure). The primary network device and the at least one secondarynetwork device are connected to a core network. A standard of theprimary network device and a standard of the secondary network devicemay be the same or different. When the standards of the two networkdevices are different, for example, one is a long term evolution (LTE)base station, and the other is a new radio (NR) base station, how thesecondary network device sends a radio resource control (RRC)configuration to the terminal device and how the terminal deviceperforms feedback when determining that the RRC configuration fails bothneed to be resolved.

SUMMARY

This application provides a failure processing method, a handovermethod, a terminal device, and a network device, to provide a manner inwhich a terminal receives an RRC configuration of a secondary networkdevice and feeds back an RRC configuration failure.

According to a first aspect, this application provides a failureprocessing method, including:

receiving, by a terminal device, a first RRC configuration of asecondary network device from the secondary network device; and

sending, by the terminal device, first indication information to aprimary network device, where the first indication information is usedto indicate that the first RRC configuration fails.

In this application, the terminal device directly receives the first RRCconfiguration of the secondary network device from the secondary networkdevice. When the first RRC configuration fails, the terminal devicesends the first indication information to the primary network device toindicate that the first RRC configuration fails. A speed is higherbecause the terminal device may directly receive the RRC configurationfrom the secondary network device. In addition, when the first RRCconfiguration fails, the terminal reports one piece of first indicationinformation to the primary network device to indicate that the first RRCconfiguration fails. Therefore, the primary network device candetermine, according to the received first indication information, thatthe first RRC configuration fails, and then can trigger a subsequentoperation.

Optionally, the sending, by the terminal device, first indicationinformation to a primary network device includes: sending, by theterminal device, a first message to the primary network device, wherethe first message includes the first indication information. Optionally,the first message is an RRC connection reestablishment message.

Optionally, the sending, by the terminal device, first indicationinformation to a primary network device includes: sending, by theterminal device, the first indication information to the primary networkdevice if a first unit of the terminal device receives second indicationinformation sent by a second unit of the terminal device, where thesecond indication information is used to indicate that the first RRCconfiguration received from the secondary network device fails, thefirst unit is configured to control an RRC connection between theprimary network device and the terminal device, and the second unit isconfigured to control an RRC connection between the secondary networkdevice and the terminal device. Optionally, the first unit is a firstRRC entity, and the second unit is a second RRC entity.

Optionally, the terminal device receives a new RRC configuration fromthe secondary network device.

According to a second aspect, an embodiment of this application providesa terminal device, where the terminal device may implement any methodprovided in the first aspect.

In a possible design, the terminal device has a function of implementingbehavior of the terminal device in any method in the first aspect, andthe function may be implemented by hardware, or may be implemented byhardware by executing corresponding software. The hardware or thesoftware includes one or more modules corresponding to the foregoingfunction. Optionally, the terminal device may be user equipment. Theterminal device may be configured to directly receive a first RRCconfiguration of a secondary network device from the secondary networkdevice. When the first RRC configuration fails, the terminal devicesends first indication information to a primary network device toindicate that the first RRC configuration fails. A speed is higherbecause the terminal device may directly receive the RRC configurationfrom the secondary network device. In addition, when the first RRCconfiguration fails, the terminal reports one piece of first indicationinformation to the primary network device to indicate that the first RRCconfiguration fails. Therefore, the primary network device candetermine, according to the received first indication information, thatthe first RRC configuration fails, and then can trigger a subsequentoperation.

In a possible design, a structure of the terminal device includes aprocessor and a transceiver, and the processor is configured to supportthe terminal device in performing a corresponding function in any methodin the first aspect, for example, generating, receiving, or processingdata and/or information in the method. The transceiver is configured to:support communication between the terminal device and another entity,and send or receive information or an instruction in any method in thefirst aspect to or from the another entity. The terminal device mayfurther include a memory. The memory is configured to be coupled to theprocessor, and the memory stores a program instruction and data that arenecessary for the terminal device.

According to a third aspect, this application provides a failureprocessing method, including:

receiving, by a terminal device, a second RRC configuration of asecondary network device from a primary network device; and

sending, by the terminal device, a second message to the primary networkdevice if the second RRC configuration fails, where the second messageis used to request RRC connection reestablishment.

In this application, the terminal device receives the second RRCconfiguration of the secondary network device from the primary networkdevice. When the second RRC configuration fails, the terminal devicesends the second message to the primary network device to request RRCconnection reestablishment, to enable that the terminal device canobtain a correct RRC configuration through the request.

Optionally, the second message includes third indication information,and the third indication information is used to indicate that the secondRRC configuration fails.

Optionally, the sending, by the terminal device, a second message to theprimary network device if the second RRC configuration fails includes:sending, by the terminal device, the second message to the primarynetwork device if a first unit of the terminal device receives fourthindication information sent by a second unit of the terminal device,where the fourth indication information is used to indicate that thesecond RRC configuration received from the primary network device fails,the first unit is configured to control an RRC connection between theprimary network device and the terminal device, and the second unit isconfigured to control an RRC connection between the secondary networkdevice and the terminal device. Optionally, the first unit is a firstRRC entity, and the second unit is a second RRC entity.

Optionally, the terminal device receives a third RRC configuration ofthe primary network device from the primary network device. If the thirdRRC configuration fails, the terminal device performs at least one ofthe following actions: stopping executing the second RRC configuration,releasing the second RRC configuration, and suspending a radio bearer ofthe secondary network device.

According to a fourth aspect, an embodiment of this application providesa terminal device, where the terminal device may implement any methodprovided in the third aspect.

In a possible design, the terminal device has a function of implementingbehavior of the terminal device in any method in the third aspect, andthe function may be implemented by hardware, or may be implemented byhardware by executing corresponding software. The hardware or thesoftware includes one or more modules corresponding to the foregoingfunction. Optionally, the terminal device may be user equipment. Theterminal device may be configured to receive a second RRC configurationof a secondary network device from a primary network device. When thesecond RRC configuration fails, the terminal device sends a secondmessage to the primary network device to request RRC connectionreestablishment, to enable that the terminal device can obtain a correctRRC configuration through the request.

In a possible design, a structure of the terminal device includes aprocessor and a transceiver, and the processor is configured to supportthe terminal device in performing a corresponding function in any methodin the third aspect, for example, generating, receiving, or processingdata and/or information in the method. The transceiver is configured to:support communication between the terminal device and another entity,and send or receive information or an instruction in any method in thethird aspect to or from the another entity. The terminal device mayfurther include a memory. The memory is configured to be coupled to theprocessor, and the memory stores a program instruction and data that arenecessary for the terminal device.

According to a fifth aspect, this application provides a failureprocessing method, including:

receiving, by a primary network device, first indication informationfrom a terminal device, where the first indication information is usedto indicate that a first RRC configuration of a secondary network devicefails, and the first RRC configuration is received by the terminaldevice from the secondary network device; and

sending, by the primary network device, a first request message to thesecondary network device, where the first request message is used torequest the secondary network device to update an RRC configuration orrequest to release the secondary network device.

Optionally, the first request message includes the first indicationinformation.

According to a sixth aspect, an embodiment of this application providesa network device, where the network device may implement any methodprovided in the fifth aspect.

In a possible design, the network device has a function of implementingbehavior of the primary network device in any method in the fifthaspect, and the function may be implemented by hardware, or may beimplemented by hardware by executing corresponding software. Thehardware or the software includes one or more modules corresponding tothe foregoing function. Optionally, the network device may be a basestation, a transmission reception point, or the like. The network devicemay be configured to receive first indication information from aterminal device, where the first indication information is used toindicate that a first RRC configuration of a secondary network devicefails. The primary network device sends a first request message to thesecondary network device, where the first request message is used torequest the secondary network device to update an RRC configuration orrequest to release the secondary network device.

In a possible design, a structure of the network device includes aprocessor and a transceiver; and the processor is configured to supportthe network device in performing a corresponding function in any methodin the fifth aspect, for example, generating, receiving, or processingdata and/or information in the method. The transceiver is configured to:support communication between the network device and another entity, andsend or receive information or an instruction in any method in the fifthaspect to or from the another entity. The network device may furtherinclude a memory. The memory is configured to be coupled to theprocessor, and the memory stores a program instruction and data that arenecessary for the network device.

According to a seventh aspect, this application provides a failureprocessing method, including:

receiving, by a primary network device, a second message from a terminaldevice if a second RRC configuration of a secondary network devicefails, where the second message is used to indicate RRC connectionreestablishment, and the second RRC configuration is received by theterminal device from the primary network device; and

sending, by the primary network device, a sixth message to the terminaldevice, where the sixth message is used to reestablish a signaling radiobearer (SRB).

Optionally, the second message includes third indication information,and the third indication information is used to indicate that the secondRRC configuration fails.

According to an eighth aspect, an embodiment of this applicationprovides a network device, where the network device may implement anymethod provided in the seventh aspect.

In a possible design, the network device has a function of implementingbehavior of the primary network device in any method in the seventhaspect, and the function may be implemented by hardware, or may beimplemented by hardware by executing corresponding software. Thehardware or the software includes one or more modules corresponding tothe foregoing function. Optionally, the network device may be a basestation, a transmission reception point, or the like. The network devicemay be configured to receive a second message from a terminal device ifa second RRC configuration of a secondary network device fails, wherethe second message is used to indicate RRC connection reestablishment.The primary network device sends a sixth message to the terminal device,where the sixth message is used to reestablish an SRB.

In a possible design, a structure of the network device includes aprocessor and a transceiver, and the processor is configured to supportthe network device in performing a corresponding function in any methodin the seventh aspect, for example, generating, receiving, or processingdata and/or information in the method. The transceiver is configured to:support communication between the network device and another entity, andsend or receive information or an instruction in any method in theseventh aspect to or from the another entity. The network device mayfurther include a memory. The memory is configured to be coupled to theprocessor, and the memory stores a program instruction and data that arenecessary for the network device.

According to a ninth aspect, this application provides a handovermethod, including:

sending, by a first primary network device, a third message to a secondprimary network device, where the third message is used to requesthandover, and the third message includes a capability coordinationresult between the first primary network device and a secondary networkdevice; and

receiving, by the first primary network device, a configuration of thesecond primary network device that is sent by the second primary networkdevice, where the configuration of the second primary network device isassociated with the capability coordination result.

In this application, the first primary network device directly sends thecapability coordination result between the first primary network deviceand the secondary network device to the second primary network device,so that the second primary network device generates the configurationbased on the capability coordination result without obtaining andunderstanding a configuration of the secondary network device, and itcan be enabled that the second primary network device can successfullygenerate the configuration in a handover process.

Optionally, the capability coordination result includes a size of alayer 2 buffer that can be used by the first primary network deviceand/or a band combination that can be used by the first primary networkdevice.

Optionally, the first primary network device receives a configuration ofthe secondary network device; and

the first primary network device sends the configuration of the secondprimary network device and the configuration of the secondary networkdevice to a terminal device.

Optionally, the receiving, by the first primary network device, aconfiguration of the secondary network device includes: receiving, bythe first primary network device, the configuration of the secondarynetwork device from the second primary network device.

Optionally, the first primary network device receives a fourth messagefrom the terminal device if the configuration of the secondary networkdevice fails, where the fourth message is used to indicate RRCconnection reestablishment.

According to a tenth aspect, an embodiment of this application providesa network device, where the network device may implement any methodprovided in the ninth aspect.

In a possible design, the network device has a function of implementingbehavior of the first primary network device in any method in the ninthaspect, and the function may be implemented by hardware, or may beimplemented by hardware by executing corresponding software. Thehardware or the software includes one or more modules corresponding tothe foregoing function. Optionally, the network device may be a basestation, a transmission reception point, or the like. The network devicemay be configured to directly send a capability coordination resultbetween the first primary network device and a secondary network deviceto a second primary network device, so that the second primary networkdevice generates a configuration based on the capability coordinationresult without obtaining and understanding a configuration of thesecondary network device, and it can be enabled that the second primarynetwork device can successfully generate the configuration in a handoverprocess.

In a possible design, a structure of the network device includes aprocessor and a transceiver, and the processor is configured to supportthe network device in performing a corresponding function in any methodin the ninth aspect, for example, generating, receiving, or processingdata and/or information in the method. The transceiver is configured to:support communication between the network device and another entity, andsend or receive information or an instruction in any method in the ninthaspect to or from the another entity. The network device may furtherinclude a memory. The memory is configured to be coupled to theprocessor, and the memory stores a program instruction and data that arenecessary for the network device.

According to an eleventh aspect, an embodiment of this applicationprovides a communications device, including a first unit and a secondunit, where

the second unit generates second indication information if the secondunit determines that a first RRC configuration of a secondary networkdevice that is received by the communications device from the secondarynetwork device fails, where the second indication information is used toindicate that the first RRC configuration fails; and

the second unit sends the second indication information to the firstunit, where

the first unit is configured to control an RRC connection between aprimary network device and the communications device, and the secondunit is configured to control an RRC connection between the secondarynetwork device and the communications device.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

According to a twelfth aspect, an embodiment of this applicationprovides a communications device, including a first unit and a secondunit, where

the second unit generates fourth indication information if the secondunit determines that a second RRC configuration of a secondary networkdevice that is received by the communications device from a primarynetwork device fails, where the fourth indication information is used toindicate that the second RRC configuration fails; and

the second unit sends the fourth indication information to the firstunit, where

the first unit is configured to control an RRC connection between theprimary network device and the communications device, and the secondunit is configured to control an RRC connection between the secondarynetwork device and the communications device.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

According to a thirteenth aspect, an embodiment of this applicationprovides a communications device, including a first unit and a secondunit, where

the first unit generates fifth indication information if the first unitdetermines that a third RRC configuration of a secondary network devicethat is received by the communications device from a primary networkdevice fails, where the fifth indication information is used to indicatethat the third RRC configuration fails; and

the first unit sends the fifth indication information to the secondunit, where

the first unit is configured to control an RRC connection between theprimary network device and the communications device, and the secondunit is configured to control an RRC connection between the secondarynetwork device and the communications device.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

According to a fourteenth aspect, an embodiment of this applicationprovides a communications device, including a first unit and a secondunit, where

the second unit sends failure indication information to the first unit,where the failure indication information is used to indicate that a linkbetween the communications device and a secondary network device fails;and the first unit receives the failure indication information, where

the first unit is configured to control an RRC connection between aprimary network device and the communications device, and the secondunit is configured to control an RRC connection between the secondarynetwork device and the communications device.

Optionally, the failure indication information is specifically used toindicate any one of the following cases: a timer expires, a quantity ofretransmission times exceeds a maximum quantity of times, random accessfails, a secondary-cell group change fails, a key fails, a check fails,integrity protection fails, a secondary network configuration receivedfrom the secondary network device fails, and a secondary networkconfiguration received from a primary network device fails.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

The communications device in the tenth to the fourteenth aspects may be,for example, a terminal device or a baseband chip.

According to a fifteenth aspect, an embodiment of this applicationprovides a computer storage medium, configured to store a computersoftware instruction used by the terminal device provided in the secondaspect, and the computer software instruction includes a programdesigned to execute the method in the first aspect; or configured tostore a computer software instruction used by the network deviceprovided in the fourth aspect, and the computer software instructionincludes a program designed to execute the method in the third aspect.

According to a sixteenth aspect, an embodiment of this applicationprovides a computer storage medium, configured to store a computersoftware instruction used by the terminal device provided in the sixthaspect, and the computer software instruction includes a programdesigned to execute the method in the fifth aspect; or configured tostore a computer software instruction used by the network deviceprovided in the eighth aspect, and the computer software instructionincludes a program designed to execute the method in the seventh aspect;or configured to store a computer software instruction used by theterminal device provided in the tenth aspect, and the computer softwareinstruction includes a program designed to execute the method in theninth aspect.

According to a seventeenth aspect, this application further provides acomputer program product that includes an instruction, and when thecomputer program product runs on a computer, the computer is enabled toperform the method according to the first aspect or the third aspect.The computer program product includes a computer execution instruction,and the computer execution instruction is stored in a computer-readablestorage medium. A processor of a terminal device may read the computerexecution instruction from the computer-readable storage medium. Theprocessor executes the computer execution instruction, so that theterminal device performs a step performed by the terminal device in theforegoing methods provided in the embodiments of this application, or afunctional unit corresponding to the step is deployed for the terminaldevice.

According to an eighteenth aspect, this application further provides acomputer program product that includes an instruction, and when thecomputer program product runs on a computer, the computer is enabled toperform the method according to the fifth aspect or the seventh aspect.The computer program product includes a computer execution instruction,and the computer execution instruction is stored in a computer-readablestorage medium. A processor of a network device may read the computerexecution instruction from the computer-readable storage medium. Theprocessor executes the computer execution instruction, so that thenetwork device performs a step performed by the primary network devicein the foregoing methods provided in the embodiments of thisapplication, or a functional unit corresponding to the step is deployedfor the network device.

According to a nineteenth aspect, this application further provides acomputer program product that includes an instruction, and when thecomputer program product runs on a computer, the computer is enabled toperform the method according to the ninth aspect. The computer programproduct includes a computer execution instruction, and the computerexecution instruction is stored in a computer-readable storage medium. Aprocessor of a network device may read the computer executioninstruction from the computer-readable storage medium. The processorexecutes the computer execution instruction, so that the network deviceperforms a step performed by the first primary network device in theforegoing method provided in the embodiments of this application, or afunctional unit corresponding to the step is deployed for the networkdevice.

According to a twentieth aspect, this application further provides achip system. The chip system includes a processor, configured to supporta terminal device in implementing the functions in the foregoingaspects, for example, generating, receiving, or processing data and/orinformation in the foregoing methods. In a possible design, the chipsystem further includes a memory. The memory is configured to store aprogram instruction and data that are necessary for the terminal device.The chip system may include a chip, or may include a chip and anotherdiscrete device.

According to a twenty-first aspect, this application further provides achip system. The chip system includes a processor, configured to supporta network device in implementing the functions in the foregoing aspects,for example, generating, receiving, or processing data and/orinformation in the foregoing methods. In a possible design, the chipsystem further includes a memory. The memory is configured to store aprogram instruction and data that are necessary for the network device.The chip system may include a chip, or may include a chip and anotherdiscrete device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of multi-connectivity according to thisapplication;

FIG. 2(a) is a structural diagram of a network according to thisapplication;

FIG. 2(b) is a structural diagram of another network according to thisapplication;

FIG. 3(a) is a flowchart of a failure processing method according tothis application;

FIG. 3(b) is a flowchart of another failure processing method accordingto this application;

FIG. 4 is a flowchart of a handover method according to thisapplication;

FIG. 5 is a schematic structural diagram of a network device accordingto this application;

FIG. 6(a) is a schematic structural diagram of a terminal deviceaccording to this application;

FIG. 6(b) is a schematic structural diagram of a terminal deviceaccording to this application;

FIG. 7 is a schematic structural diagram of an apparatus according tothis application;

FIG. 8 is a schematic structural diagram of a terminal device accordingto this application;

FIG. 9 is a schematic structural diagram of a network device accordingto this application; and

FIG. 10 is a schematic structural diagram of a communications deviceaccording to this application.

DESCRIPTION OF EMBODIMENTS

The following clearly describes technical solutions in the embodimentsof this application with reference to the accompanying drawings in theembodiments of this application.

Network architectures and service scenarios described in the embodimentsof this application are intended to describe the technical solutions inthe embodiments of this application more clearly, but do not constitutea limitation to the technical solutions provided in the embodiments ofthis application. A person of ordinary skill in the art may know that asthe network architectures evolve and a new service scenario emerges, thetechnical solutions provided in the embodiments of this application arealso applicable to a similar technical problem.

This application may be applied to an existing cellular communicationssystem, for example, systems such as a global system for mobilecommunications (GSM), a wideband code division multiple access (WCDMA)system, and a long term evolution (LTE) system; or is applicable to a5th generation mobile communications system (5rd-Generation, 5G forshort) system, for example, communications systems such as an accessnetwork that uses new radio (NR), a cloud radio access network (CRAN),and an LTE access network connected to a 5G core network; or may beextended to a similar wireless communications system, such as a wirelessfidelity (Wireless-Fidelity, Wi-Fi for short) system, a worldwideinteroperability for microwave access (WiMAX) system, and anotherrelated cellular system in the 3rd Generation Partnership Project(3GPP); or is applicable to another wireless communications system thatuses an orthogonal frequency division multiplexing (OFDM) accesstechnology; and is also applicable to a future wireless communicationssystem.

For ease of understanding, some terminologies in this application aredescribed below.

(1) A terminal device, also referred to as user equipment (UE) or aterminal, is a device that provides a user with voice and/or dataconnectivity, for example, a handheld device, an in-vehicle device, awearable device, a computing device, or a control device having awireless connection function or a wireless communication function, oranother processing device connected to a wireless modem, and mobilestations (MS) in various forms. Common terminal devices include a mobilephone, a tablet computer (pad), a notebook computer, a palmtop computer,a mobile internet device (MID), and a wearable device such as asmartwatch, a smart band, or a pedometer. For ease of description, inthis application, the devices mentioned above are collectively referredto as terminal devices.

(2) A network device may be, for example, a base station, and is adevice that connects a terminal device to a wireless network. Thenetwork device includes but is not limited to an evolved NodeB (eNB), aradio network controller (RNC), a NodeB (NB), a base station controller(BSC), a base transceiver station (BTS), a home eNodeB (for example,Home evolved NodeB or Home Node B, HNB for short), a baseband unit(BBU), a new radio NodeB (g NodeB, gNB for short), a transmissionreception point (TRP), a transmitting point (TP), a mobile switchingcenter, and the like. In addition, the network device may include aWi-Fi access point (AP) and the like. An apparatus that directlycommunicates with the terminal device through a wireless channel isusually a base station. The base station may include various forms ofmacro base stations, micro base stations, relay stations, access points,remote radio units (RRU), and the like. Certainly, another networkdevice having a wireless communication function may wirelesslycommunicate with the terminal device. This is not uniquely limited inthis application. In different systems, a device having a function of abase station may have a different name. For example, in an LTE network,the device is referred to as an evolved NodeB (eNB); and in a 3rdgeneration (3G) network, the device is referred to as a NodeB.

The term “and/or” in this application describes only an associationrelationship for describing associated objects and represents that threerelationships may exist. For example, A and/or B may represent thefollowing three cases: only A exists, both A and B exist, and only Bexists. In addition, the character “/” in this specification generallyindicates an “or” relationship between the associated objects.

The following describes in more detail the solutions provided in theembodiments of this application with reference to the accompanyingdrawings.

FIG. 2(a) is a structural diagram of a network according to thisapplication. A terminal device may interact with a primary networkdevice and at least one secondary network device (one secondary networkdevice is used as an example in the figure), and the terminal deviceincludes a first unit and a second unit. The first unit may be a firstRRC entity, a first RRC functional unit, or a first RRC unit, and isconfigured to control an RRC connection between the primary networkdevice and the terminal device. The second unit may be a second RRCentity, a second RRC functional unit, or a second RRC unit, and isconfigured to control an RRC connection between the secondary networkdevice and the terminal device.

For example, a core network is an evolved packet core (EPC). The primarynetwork device is an LTE base station (such as an eNB), and a controlplane connection and a user plane connection may be established betweenthe primary network device and the EPC for the terminal device. Thesecondary network device is an NR base station (such as a gNB), and onlya user plane connection can be established between the secondary networkdevice and the EPC. The first unit is an LTE RRC entity, and isresponsible for managing LTE radio resources. The second unit is an NRRRC entity, and is responsible for managing NR radio resources. Inaddition, for example, an S1 interface may be used between the corenetwork and the primary network device; an S1 interface may be usedbetween the core network and the secondary network device; and an X2interface may be used between the primary network device and thesecondary network device.

For another example, a core network is a next generation core (NGC), a5G core network (5G-CN), or a 5G core (5GC). An example in which thecore network is an NGC is used for description below. The primarynetwork device is an LTE base station (such as an eNB), and a controlplane connection and a user plane connection may be established betweenthe primary network device and the NGC for the terminal device. Thesecondary network device is an NR base station (such as a gNB), and onlya user plane connection can be established between the secondary networkdevice and the NGC. The first unit is an LTE RRC entity, and isresponsible for LTE radio resources. The second unit is an NR RRCentity, and is responsible for managing NR radio resources. In addition,for example, a next generation (NG) interface may be used between thecore network and the primary network device; an NG interface may be usedbetween the core network and the secondary network device; and an Xninterface (namely, a next generation interface) may be used between theprimary network device and the secondary network device.

For another example, a core network is an NGC, a 5G-CN, or a 5GC. Anexample in which the core network is an NGC is used for descriptionbelow. The primary network device is an NR base station (such as a gNB),and a control plane connection and a user plane connection may beestablished between the primary network device and the NGC for theterminal device. The secondary network device is an LTE base station(such as an eNB), and only a user plane connection can be establishedbetween the secondary network device and the NGC. The first unit is anNR RRC entity, and is responsible for managing NR radio resources. Thesecond unit is an LTE RRC entity, and is responsible for managing LTEradio resources. In addition, for example, an NG interface may be usedbetween the core network and the primary network device; an NG interfacemay be used between the core network and the secondary network device;and an Xn interface (namely, a next generation interface) may be usedbetween the primary network device and the secondary network device.

Certainly, alternatively, the core network may be another core network,the primary network device may be another network device, such asvarious types of network devices mentioned above, and the secondarynetwork device may also be another network device, such as various typesof network devices mentioned above.

In this application, standards of the primary network device and thesecondary network device may be the same or different. The followingmainly provides description for a case in which the standards of theprimary network device and the secondary network device are different.For example, the primary network device is an LTE base station, and thesecondary network device is an NR base station; or the primary networkdevice is an NR base station, and the secondary network device is an LTEbase station. In addition, for ease of description, in this application,the first unit has a same standard as the primary network device, andthe second unit has a same standard as the secondary network device. Forexample, when the primary network device is an NR base station, and thesecondary network device is an LTE base station, the first unit isresponsible for managing NR radio resources, for example, the first unitis an NR RRC entity; and the second unit is responsible for managing LTEradio resources, for example, the second unit is an LTE RRC entity. Foranother example, when the primary network device is an LTE base station,and the secondary network device is an NR base station, the first unitis responsible for managing LTE radio resources, for example, the firstunit is an LTE RRC entity; and the second unit is responsible formanaging NR radio resources, for example, the second unit is an NR RRCentity.

The terminal device may obtain radio resources from both an airinterface of the primary network device and an air interface of thesecondary network device to transmit data, thereby obtaining a gain of atransmission rate.

In this application, the first unit and the second unit are responsiblefor configurations in their respective standards, and do not understandeach other's configuration.

The primary network device and the secondary network device areindependent of each other. From a perspective of a network side, theprimary network device and the secondary network device each have RRCand may generate a complete RRC message. In a scenario shown in FIG.2(a), an RRC message (carrying an RRC configuration of the secondarynetwork device) generated by the secondary network device is sent to theprimary network device; and the primary network device uses the RRCmessage of the secondary network device as a container, adds thecontainer to an RRC message of the primary network device, and sends theRRC message of the primary network device to the terminal device. Inother words, the terminal device receives the RRC message of the primarynetwork device from the primary network device, the RRC message includesan RRC configuration of the primary network device and the RRCconfiguration of the secondary network device, and the RRC configurationof the secondary network device in the RRC message of the primarynetwork device is sent by the secondary network device to the primarynetwork device by using the RRC message of the secondary network device.

In an RRC configuration manner shown in FIG. 2(a), which is alsoreferred to as joint configuration in this application, the secondarynetwork device sends the RRC configuration of the secondary networkdevice to the primary network device, and the primary network devicethen sends the RRC configuration of the secondary network device to theterminal device; in addition, the primary network device may furthersend the RRC configuration of the primary network device to the terminaldevice. In other words, in the joint configuration scenario, the RRCconfiguration of the secondary network device needs to be sent to theterminal device by using the primary network device.

FIG. 2(b) is a structural diagram of another network according to thisapplication. A core network, a primary network device, a secondarynetwork device, a first unit, and a second unit in FIG. 2(b) have sametypes and same mutual relationships as the core network, the primarynetwork device, the secondary network device, the first unit, and thesecond unit in FIG. 2(a). For details, refer to the foregoingdescription. A main difference between FIG. 2(b) and FIG. 2(a) is asfollows: in FIG. 2(b), the secondary network device may directly send anRRC message to a terminal device, where the RRC message carries an RRCconfiguration of the secondary network device; and the primary networkdevice sends an RRC message to the terminal device, where the RRCmessage carries an RRC configuration of the primary network device.Therefore, in an RRC configuration manner shown in FIG. 2(b), which isalso referred to as independent configuration in this application, theRRC configuration of the primary network device and the RRCconfiguration of the secondary network device are independently sent bythe primary network device and the secondary network device to theterminal device, respectively.

The following describes in detail two failure processing methodsprovided in this application with reference to FIG. 2(a) and FIG. 2(b)respectively.

FIG. 3(a) is a flowchart of a failure processing method according tothis application. The method corresponds to the scenario shown in FIG.2(a), namely, the joint configuration scenario, and specificallyincludes the following steps.

Step 101: A primary network device sends a second RRC configuration of asecondary network device to a terminal device.

An RRC configuration is configuration information generated by an RRCentity of a network device, and is used to configure a terminal device.For example, the RRC configuration includes configurations of protocollayers, and includes but is not limited to a packet data convergenceprotocol (PDCP) configuration, a radio link control (RLC) configuration,a media access control (MAC) configuration, and a physical layerconfiguration.

Optionally, the secondary network device adds the second RRCconfiguration of the secondary network device to an RRC message of thesecondary network device, and sends the RRC message of the secondarynetwork device to the primary network device. After receiving the RRCmessage of the secondary network device, the primary network device addsthe RRC configuration of the secondary network device to an RRC messageof the primary network device, and sends the RRC message of the primarynetwork device to the terminal device. Optionally, the RRC message ofthe primary network device further carries a third RRC configuration ofthe primary network device.

Step 102: The terminal device receives the second RRC configuration ofthe secondary network device from the primary network device.

Step 103: The terminal device sends a second message to the primarynetwork device if the second RRC configuration fails.

The second message is used to request RRC connection reestablishment.Optionally, the second message is an RRC connection reestablishmentmessage. Optionally, the second message includes third indicationinformation, and the third indication information is used to indicatethat the second RRC configuration fails.

In a possible implementation, referring to FIG. 2(a), a second unit ofthe terminal device generates fourth indication information if thesecond unit determines that the second RRC configuration of thesecondary network device that is received by the terminal device fromthe primary network device fails, where the fourth indicationinformation is used to indicate that the second RRC configuration fails.Then, the second unit sends the fourth indication information to a firstunit. The terminal device sends the second message to the primarynetwork device if the first unit receives the fourth indicationinformation sent by the second unit. The second unit may be a second RRCentity of the terminal device.

In another possible implementation, referring to FIG. 2(a), a secondunit of the terminal device generates seventh indication information ifthe second unit determines that the second RRC configuration of thesecondary network device that is received by the terminal device fromthe primary network device succeeds, where the seventh indicationinformation is used to indicate that the second RRC configurationsucceeds. Then, the second unit sends the seventh indication informationto a first unit. The terminal device sends a fifth message to theprimary network device if the first unit receives the seventh indicationinformation sent by the second unit, where the fifth message is used toindicate that the second RRC configuration succeeds. The second unit maybe a second RRC entity of the terminal device.

Step 104: The primary network device receives the second message fromthe terminal device.

Step 105: The primary network device sends a sixth message to theterminal device, where the sixth message is used to reestablish an SRB.

In step 101 to step 105, the terminal device receives the second RRCconfiguration of the secondary network device from the primary networkdevice; when the terminal device determines that the second RRCconfiguration fails, to be specific, the second unit of the terminaldevice determines that the second RRC configuration fails, and sends thefourth indication information to the first unit, the terminal devicesends the second message to the primary network device to request theRRC connection reestablishment; and after receiving the second message,the primary network device sends a RRC connection reestablishmentmessage.

Optionally, before or after any one of step 101 to step 105, the methodfurther includes:

the terminal device receives the third RRC configuration of the primarynetwork device from the primary network device; and if the third RRCconfiguration fails, the terminal device performs at least one of thefollowing actions: stopping executing the second RRC configuration,releasing the second RRC configuration, and suspending a radio bearer ofthe secondary network device.

Optionally, that the terminal device performs at least one of thefollowing actions includes: if the second unit receives fifth indicationinformation sent by the first unit, the terminal device performs atleast one of the following actions, where the fifth indicationinformation is used to indicate that the third RRC configuration fails.

To be specific, when the terminal device further receives the third RRCconfiguration of the primary network device from the primary networkdevice, and the third RRC configuration fails, the first unit sends thefifth indication information to the second unit to indicate that thethird RRC configuration fails, and the terminal device further stopsexecuting the second RRC configuration, and/or releases the second RRCconfiguration, and/or suspends the radio bearer of the secondary networkdevice.

In addition, if the third RRC configuration fails, the terminal devicefurther needs to perform the following operation:

the terminal device sends a seventh message to the primary networkdevice, where the seventh message is used to request RRC connectionreestablishment. Optionally, the seventh message includes seventhindication information, and the seventh indication information is usedto indicate that the third RRC configuration of the primary networkdevice that is received by the terminal device from the primary networkdevice fails.

FIG. 3(b) is a flowchart of another failure processing method accordingto this application. The method corresponds to the scenario shown inFIG. 2(b), namely, an independent configuration scenario, andspecifically includes the following steps.

Step 201: A terminal device receives a first RRC configuration of asecondary network device from the secondary network device.

Step 202: The terminal device sends first indication information to aprimary network device.

The first indication information is used to indicate that the first RRCconfiguration fails.

Optionally, that the terminal device sends first indication informationto a primary network device includes: the terminal device sends a firstmessage to the primary network device, where the first message includesthe first indication information.

Optionally, referring to FIG. 3(b), that the terminal device sends firstindication information to a primary network device includes: theterminal device sends the first indication information to the primarynetwork device if a first unit of the terminal device receives secondindication information sent by a second unit of the terminal device,where the second indication information is used to indicate that thefirst RRC configuration received from the secondary network devicefails. In other words, the second unit sends the second indicationinformation to the first unit if the second unit determines that thefirst RRC configuration fails, and the terminal device sends the firstindication information to the primary network device if the first unitreceives the second indication information sent by the second unit.

Step 203: The primary network device receives the first indicationinformation from the terminal device.

Step 204: The primary network device sends a first request message tothe secondary network device.

The first request message is used to request the secondary networkdevice to update an RRC configuration or request to release thesecondary network device.

After updating the RRC configuration, the secondary network device sendsa new RRC configuration to the primary network device. The primarynetwork device sends the new RRC configuration to the terminal device.In other words, the terminal device receives the new RRC configurationfrom the primary network device.

It should be noted that an RRC connection reestablishment process isperformed between the primary network device and user equipment in thiscase.

Alternatively, after updating the RRC configuration, the secondarynetwork device directly sends a new RRC configuration to the terminaldevice. In other words, the terminal device receives the new RRCconfiguration from the secondary network device. In this method, theterminal device directly receives the new RRC configuration from thesecondary network device, and therefore a speed is higher than a speedin the method for receiving the new RRC configuration of the secondarynetwork device from the primary network device.

Optionally, the first request message includes the first indicationinformation.

In an alternative solution of step 204, step 204 may alternatively bereplaced with step 204 a.

Step 204 a: The primary network device releases the secondary networkdevice.

After releasing the secondary network device, the primary network devicemay be further reconnected to a new secondary network device.

Optionally, in this application, the implementation methods shown inFIG. 3(a) and FIG. 3(b) may be used as a whole for understanding. To bespecific, the terminal device may receive the first RRC configuration ofthe secondary network device from the secondary network device, and mayalso receive a second RRC configuration of the secondary network devicefrom the primary network device.

The second unit sends failure indication information to the first unitif the terminal device determines that a link between the terminaldevice and the secondary network device fails. The failure indicationinformation indicates a specific cause of the link failure. For example,the failure indication information is specifically used to indicate thata timer expires, a quantity of retransmission times exceeds a maximumquantity of times, random access fails, a secondary-cell group changefails, a key fails, a check fails, integrity protection fails, asecondary network configuration received from the secondary networkdevice fails, or a secondary network configuration received from aprimary network device fails.

The timer may be started when the terminal device detects that aphysical layer problem occurs in a primary cell of the secondary networkdevice. The quantity of retransmission times may be a quantity of timesof performing retransmission at an RLC layer, or may be a quantity oftimes of performing retransmission at another layer. That random accessfails may indicate that random access to a cell of the secondary networkdevice by the terminal device fails. That a secondary-cell group changefails may indicate that the terminal device fails to change asecondary-cell group. The secondary-cell group may be a cell group, ofthe secondary network device, that serves the terminal device. That akey fails may indicate that the terminal device cannot normally performencryption and/or decryption because of key inconsistency between theterminal device and the secondary network device. That a check fails mayindicate checking performed by the terminal device and the secondarynetwork device fails. That integrity protection fails may indicate thatintegrity protection between the terminal device and the secondarynetwork device fails. For detailed contents, refer to related contentsin 3GPP TS 36.331 and 3GPP TS 33.401. The foregoing description ismerely used as an example, but no limitation is set to the foregoingdescription.

When the failure indication information is used to indicate that thesecondary network configuration received from the secondary networkdevice fails, the failure indication information is the secondindication information described above.

When the failure indication information is used to indicate that thesecondary network configuration received from the primary network devicefails, the failure indication information is the fourth indicationinformation described above.

Optionally, the failure indication information may be generated by thesecond unit when the second unit determines that the link between theterminal device and the secondary network device fails. Alternatively, athird unit of the terminal device may generate sixth indicationinformation when determining that the link between the terminal deviceand the secondary network device fails, where the sixth indicationinformation is used to indicate that the link between the terminaldevice and the secondary network device fails; the third unit sends thesixth indication information to the second unit; and after receiving thesixth indication information, the second unit generates the failureindication information. Alternatively, a third unit may generate failureindication information when determining that the link between theterminal device and the secondary network device fails, and thendirectly send the failure indication information to the first unit.

The third unit may be a second MAC entity, a second RLC entity, a secondphysical layer unit, or an application layer entity of the terminaldevice, and the second MAC entity, the second RLC entity, or the secondphysical layer unit has a same standard as the secondary network device.

After the first unit receives the failure indication information, theterminal device sends indication information to the primary networkdevice if the failure indication information indicates that the timerexpires, where the indication information is used to indicate that thetimer expires. After receiving the indication information, the primarynetwork device does not reestablish an RRC link.

After the first unit receives the failure indication information, theterminal device sends indication information to the primary networkdevice if the failure indication information indicates that the quantityof retransmission times exceeds the maximum quantity of times, where theindication information is used to indicate that the quantity ofretransmission times exceeds the maximum quantity of times. Afterreceiving the indication information, the primary network device doesnot reestablish an RRC link.

After the first unit receives the failure indication information, theterminal device sends indication information to the primary networkdevice if the failure indication information indicates that the randomaccess fails, where the indication information is used to indicate thatthe random access fails. After receiving the indication information, theprimary network device does not reestablish an RRC link.

After the first unit receives the failure indication information, theterminal device sends indication information to the primary networkdevice if the failure indication information indicates that thesecondary-cell group change fails, where the indication information isused to indicate that the secondary-cell group change fails. Afterreceiving the indication information, the primary network device doesnot reestablish an RRC link.

After the first unit receives the failure indication information, theterminal device sends indication information to the primary networkdevice if the failure indication information indicates that the keyfails, where the indication information is used to indicate that the keyfails. After receiving the indication information, the primary networkdevice does not reestablish an RRC link.

After the first unit receives the failure indication information, theterminal device sends indication information to the primary networkdevice if the failure indication information indicates that the checkfails, where the indication information is used to indicate that thecheck fails. After receiving the indication information, the primarynetwork device does not reestablish an RRC link.

After the first unit receives the failure indication information, theterminal device sends indication information to the primary networkdevice if the failure indication information indicates that theintegrity protection fails, where the indication information is used toindicate that the integrity protection fails. After receiving theindication information, the primary network device does not reestablishan RRC link.

After the first unit receives the failure indication information, theterminal device sends the first indication information to the primarynetwork device if the failure indication information indicates that thesecondary network configuration received from the secondary networkdevice fails, where the first indication information is used to indicatethat the secondary network configuration received from the secondarynetwork device fails (that is, the first RRC configuration describedabove fails). After receiving the first indication information, theprimary network device does not reestablish an RRC link.

After the first unit receives the failure indication information, theterminal device sends a second message to the primary network device ifthe failure indication information indicates that the secondary networkconfiguration received from the primary network device fails, where thesecond message is used to request RRC connection reestablishment. Afterreceiving the second message, the primary network device reestablishesan RRC link. Optionally, the second message further includes thirdindication information, and the third indication information is used toindicate that the secondary network configuration received from theprimary network device fails (that is, the second RRC configurationdescribed above fails).

In the foregoing embodiments provided in this application, the failureprocessing methods provided in the embodiments of this application aredescribed respectively from a perspective of each network element andfrom a perspective of interaction between network elements. It may beunderstood that, to implement the foregoing function, the networkelements, such as the terminal device (for example, UE) and the networkdevice (for example, a base station), include a corresponding hardwarestructure and/or software module for performing each function. A personskilled in the art should be easily aware that units and algorithm stepsin the examples described with reference to the embodiments disclosed inthis specification can be implemented in a form of hardware or in a formof a combination of hardware and computer software in this application.Whether a function is implemented by hardware or in a manner of drivinghardware by computer software depends on particular applications anddesign constraints of the technical solutions. A person skilled in theart may use different methods to implement the described functions foreach particular application, but it should not be considered that theimplementation goes beyond the scope of this application.

In a scenario of handover between primary network devices, a firstprimary network device connected to a terminal device needs to be handedover to a second primary network device, a secondary network deviceconnected to the terminal device remains unchanged, and a configurationof the secondary network device remains unchanged. Commonly, a firstprimary network device, a second primary network device, and a secondarynetwork device have same standards, for example, they are all LTEnetwork devices, or are all NR network devices. Therefore, a handoverprocedure is as follows: The first primary network device sends aconfiguration of the secondary network device to the second primarynetwork device; and after receiving the configuration of the secondarynetwork device, the second primary network device may read andunderstand the configuration, and therefore may generate a configurationbased on the configuration and a capability of the terminal device, andenable that the final configuration does not exceed the capability ofthe terminal device.

In consideration of another application scenario, a first primarynetwork device and a second primary network device have same standards,and the standards are different from a standard of a secondary networkdevice. In this case, according to the foregoing handover procedure,because the second primary network device cannot understand aconfiguration of the secondary network device, the first primary networkdevice cannot be handed over to the second primary network deviceaccording to the foregoing handover method.

Therefore, this application further provides a handover method. As shownin FIG. 4 , the method includes the following steps.

Step 301: A first primary network device sends a third message to asecond primary network device.

The third message is used to request handover. For example, the thirdmessage is a handover request message, and the third message includes acapability coordination result between the first primary network deviceand a secondary network device.

Optionally, the capability coordination result includes a size of alayer 2 buffer that can be used by the first primary network deviceand/or a band combination that can be used by the first primary networkdevice.

The layer 2 buffer is a layer 2 buffer of a terminal device, and theband combination is a band combination of the terminal device.

Step 302: The second primary network device generates a configuration ofthe second primary network device based on the capability negotiationresult between the first primary network device and the secondarynetwork device.

In other words, the configuration of the second primary network deviceis associated with the capability coordination result.

Optionally, the configuration is an RRC configuration.

Step 303: The second primary network device sends the configuration ofthe second primary network device to the first primary network device.

Step 304: The first primary network device receives the configuration ofthe second primary network device that is sent by the second primarynetwork device.

By using step 301 to step 304, the first primary network device directlysends the capability coordination result between the first primarynetwork device and the secondary network device to the second primarynetwork device, so that the second primary network device generates theconfiguration based on the capability coordination result withoutobtaining and understanding a configuration of the secondary networkdevice, and it can be enabled that the second primary network device cansuccessfully generate the configuration in a handover process.

Optionally, the first primary network device may further receive aconfiguration of the secondary network device. Further, the firstprimary network device sends the configuration of the second primarynetwork device and the configuration of the secondary network device tothe terminal device. That the first primary network device receives aconfiguration of the secondary network device includes: the firstprimary network device receives the configuration of the secondarynetwork device from the second primary network device, or the firstprimary network device receives the configuration of the secondarynetwork device from the secondary network device.

To be specific, by using the foregoing steps, the second primary networkdevice sends the configuration of the second primary network device tothe first primary network device. Optionally, the second primary networkdevice further sends the configuration of the secondary network deviceto the first primary network device (or the secondary network devicesends the configuration of the secondary network device to the firstprimary network device). After receiving the configuration of the secondprimary network device, optionally, the first primary network devicefurther receives the configuration of the secondary network device. Thefirst primary network device sends the configuration of the secondprimary network device to the terminal device, and optionally, furthersends the configuration of the secondary network device to the terminaldevice.

Optionally, if the terminal device receives the configuration of thesecondary network device that is sent by the first primary networkdevice, and the configuration of the secondary network device fails, theterminal device sends a fourth message to the first primary networkdevice, where the fourth message is used to indicate RRC connectionreestablishment.

For a detailed process of a failure processing method used when theterminal device receives the configuration of the secondary networkdevice that is sent by the first primary network device and theconfiguration of the secondary network device fails, refer to theforegoing description and the description shown in FIG. 3(a). Detailsare not described herein again.

The following provides description by using band combinationcoordination as an example. For capability coordination of bandcombination, an optional solution is to maintain a band combinationlist. For example, as shown in Table 1, the first column is an index,the second column is a band combination that can be used by the firstprimary network device, and the third column is a band combination thatcan be used by the secondary network device when the first primarynetwork device uses the band combination in the second column. Such acombination exists because a same radio frequency chain of a terminaldevice may be used in different bands, and the same radio frequencychain cannot be simultaneously used by the first primary network deviceand the secondary network device.

A network side can obtain information in Table 1 from a capability ofthe terminal device. Specifically, the first primary network device onlyneeds to know a band combination that is of the first primary networkdevice and that corresponds to an index, and the secondary networkdevice only needs to know a band combination that is of the secondarynetwork device and that corresponds to an index. In a capabilitycoordination process, the first primary network device selects a bandcombination, and sends a corresponding index to the secondary networkdevice. Therefore, the secondary network device may know a bandcombination that can be used by the secondary network device, therebyensuring that a final configuration does not exceed the capability ofthe terminal device. For example, if a band combination selected by thefirst primary network device is 1, 3, and 5, the first primary networkdevice sends an index 4 to the secondary network device, and thereforethe secondary network device learns that a band combination that can beused by the secondary network device is 2, 3, and 4.

TABLE 1 Band combination of the Band combination of the Index firstprimary network device secondary network device 1 1, 2, 3, 4 2, 3, 5 22, 3, 4 2, 3, 4, 5 3 4, 5 1, 2, 3 4 1, 3, 5 2, 3, 4

After determining the band combination that can be used by the firstprimary network device, for example, the band combination that can beused is 1, 3, and 5, the first primary network device sends, to thesecond primary network device, the band combination that can be used bythe first primary network device.

Then, the layer 2 buffer is used as an example. Assuming that a size ofthe layer 2 buffer of the terminal device is 1 G, the first primarynetwork device coordinates with the secondary network device, forexample, to finally determine that the size of the layer 2 buffer thatcan be used by the first primary network device is 600 M, and a size ofa layer 2 buffer that can be used by the secondary network device is 400M.

After determining the size of the layer 2 buffer and the bandcombination that can be used by the first primary network device, thefirst primary network device sends, to the second primary networkdevice, the size of the layer 2 buffer and the band combination that canbe used by the first primary network device. The second primary networkdevice then generates the configuration, for example, generates an RRCconfiguration, and sends the configuration to the first primary networkdevice. The first primary network device then sends the configuration tothe terminal device.

Optionally, the secondary network device generates the configurationbased on the size of the layer 2 buffer and a band combination that canbe used by the secondary network device, and sends the configuration tothe second primary network device. The second primary network devicesends the configuration of the secondary network device and theconfiguration of the second primary network device together to the firstprimary network device, and the first primary network device sends theconfigurations to the terminal device.

Based on a same concept, an embodiment of this application furtherprovides a network device 500. As shown in FIG. 5 , the network device500 may be configured to perform the method performed by the primarynetwork device in the foregoing failure processing methods and themethod performed by the first primary network device in the foregoinghandover method. The network device 500 includes one or more remoteradio units (RRU) 501 and one or more baseband units (BBU) 502. The RRU501 may be referred to as a transceiver unit, a transceiver, atransceiver circuit, a transceiver, or the like; and may include atleast one antenna 5011 and a radio frequency unit 5012. The RRU 501 ismainly configured to receive/send a radio frequency signal and convert aradio frequency signal and a baseband signal. The BBU 502 is mainlyconfigured to perform baseband processing, control the network device,and the like. The RRU 501 and the BBU 502 may be physically disposedtogether; or the RRU 501 and the BBU 502 may be physically separated, orin other words, the RRU 501 and the BBU 502 are devices in a distributednetwork

The BBU 502 is a control center of the network device, or may bereferred to as a processing unit, and is mainly configured to completebaseband processing functions such as channel coding, multiplexing,modulation, and spectrum spreading. For example, the BBU (processingunit) may be configured to control the network device to perform themethod performed by the primary network device in any one of theforegoing failure processing methods and the method performed by thefirst primary network device in the foregoing handover method.

In an example, the BBU 502 may include one or more boards, and aplurality of boards may jointly support a radio access network (such asan LTE network) of a single access standard, or may support radio accessnetworks of different access standards. The BBU 502 further includes amemory 5021 and a processor 5022. The memory 5021 is configured to storea necessary instruction and necessary data. The processor 5022 isconfigured to control the network device to perform a necessary action,for example, is configured to control the network device to perform themethod performed by the network device in any one of the foregoingembodiments. The memory 5021 and the processor 5022 may serve one ormore boards. In other words, a memory and a processor may be separatelydisposed on each board. Alternatively, a plurality of boards may use asame memory and processor. In addition, a necessary circuit is furtherdisposed on each board.

On an uplink, an uplink signal (including data and the like) sent by aterminal device is received by using the antenna 5011. On a downlink, adownlink signal (including data and/or control information) is sent tothe terminal device by using the antenna 5011. In the processor 5022,service data and a signaling message are processed, and these unitsperform processing according to a radio access technology (such asaccess technologies in LTE, NR, and other evolved systems) used in aradio access network. The processor 5022 is further configured tocontrol and manage an action of the network device, and is configured toperform processing performed by the network device in the foregoingembodiment. The processor 5022 is further configured to support thenetwork device in performing processing procedures described in FIG.3(a) and FIG. 3(b) and performed by the primary network device and themethod described in FIG. 4 and performed by the first primary networkdevice.

It may be understood that FIG. 5 shows only a simplified design of thenetwork device. In actual application, the network device may includeany quantity of antennas, memories, processors, radio frequency units,RRUs, BBUs, and the like, and all network devices that can implementthis application fall within the protection scope of this application.

Specifically, in this application, for example, the RRU 501 is referredto as a transceiver. In this case, the transceiver and the processor inthe network device 500 may be specifically configured to:

The transceiver is configured to receive first indication informationfrom the terminal device, where the first indication information is usedto indicate that a first RRC configuration of a secondary network devicefails, and the first RRC configuration is received by the terminaldevice from the secondary network device.

The transceiver is further configured to send a first request message tothe secondary network device, where the first request message is used torequest the secondary network device to update an RRC configuration orrequest to release the secondary network device.

Optionally, the first request message includes the first indicationinformation.

The transceiver and the processor in the network device 500 may befurther specifically configured to.

If a second RRC configuration of a secondary network device fails, thetransceiver is configured to receive a second message from the terminaldevice, where the second message is used to indicate RRC connectionreestablishment, and the second RRC configuration is received by theterminal device from the primary network device.

The transceiver is further configured to initiate the RRC connectionreestablishment to the terminal device.

Optionally, the second message includes third indication information,and the third indication information is used to indicate that the secondRRC configuration fails.

The transceiver and the processor in the network device 500 may befurther specifically configured to.

The transceiver is configured to send a third message to a secondprimary network device, where the third message is used to requesthandover, and the third message includes a capability coordinationresult between the first primary network device and a secondary networkdevice.

The transceiver is further configured to receive a configuration of thesecond primary network device that is sent by the second primary networkdevice, where the configuration of the second primary network device isassociated with the capability coordination result.

Optionally, the capability coordination result includes a size of alayer 2 buffer that can be used by the first primary network deviceand/or a band combination that can be used by the first primary networkdevice.

Optionally, the transceiver is further configured to receive aconfiguration of the secondary network device.

The transceiver is further configured to send the configuration of thesecond primary network device and the configuration of the secondarynetwork device to the terminal device.

Optionally, the transceiver is further configured to receive theconfiguration of the secondary network device from the second primarynetwork device.

Optionally, if the configuration of the secondary network device fails,the transceiver is further configured to receive a fourth message fromthe terminal device, where the fourth message is used to indicate RRCconnection reestablishment.

Based on a same concept, an embodiment of this application furtherprovides a terminal device 600. For ease of description, FIG. 6(a) showsonly main components of the terminal device. As shown in FIG. 6(a), theterminal device 600 includes a processor, a memory, a control circuit,an antenna, and an input/output apparatus. The processor is mainlyconfigured to: process a communications protocol and communication data,control the entire terminal device, execute a software program, andprocess data of the software program, for example, configured to supportthe terminal device 600 in performing the method performed by theterminal device in any one of the foregoing embodiments. The memory ismainly configured to store the software program and the data. Thecontrol circuit is mainly configured to convert a baseband signal and aradio frequency signal and process a radio frequency signal. The controlcircuit, together with the antenna, may also be referred to as atransceiver that is mainly configured to receive/send a radio frequencysignal in an electromagnetic wave form. The input/output apparatus, suchas a touchscreen, a display screen, or a keyboard, is mainly configuredto: receive data entered by a user and output data to the user.

After the terminal device is powered on, the processor may read asoftware program in a storage unit, explain and execute an instructionof the software program, and process data of the software program. Whendata needs to be sent in a wireless manner, the processor performsbaseband processing on the to-be-sent data, and outputs a basebandsignal to a radio frequency circuit. The radio frequency circuitperforms radio frequency processing on the baseband signal, and thensends a radio frequency signal by using the antenna in anelectromagnetic wave form. When data is sent to the terminal device 600,the radio frequency circuit receives a radio frequency signal by usingthe antenna, converts the radio frequency signal into a baseband signal,and outputs the baseband signal to the processor, and the processorconverts the baseband signal into data and processes the data.

A person skilled in the art may understand that, for ease ofdescription, FIG. 6(a) shows only one memory and one processor.Actually, the terminal device may include a plurality of processors anda plurality of memories. The memory may also be referred to as a storagemedium, a storage device, or the like. This is not limited in thisapplication.

In an optional implementation, the processor may include a basebandprocessor and a central processing unit. The baseband processor ismainly configured to process a communications protocol and communicationdata, and the central processing unit is mainly configured to: controlthe entire terminal device 600, execute a software program, and processdata of the software program. Functions of the baseband processor andthe central processing unit are integrated into the processor in FIG.6(a). A person skilled in the art may understand that the basebandprocessor and the central processing unit each may be an independentprocessor, and they are interconnected by using a technology such as abus. A person skilled in the art may understand that the terminal devicemay include a plurality of baseband processors to adapt to differentnetwork standards, the terminal device 600 may include a plurality ofcentral processing units to enhance a processing capability of theterminal device 600, and all components of the terminal device 600 maybe connected through various buses. The baseband processor may also beexpressed as a baseband processing circuit or a baseband processingchip. The central processing unit may also be expressed as a centralprocessing circuit or a central processing chip. A function ofprocessing a communications protocol and communication data may be builtinto the processor, or may be stored in a storage unit in a form of asoftware program. The processor executes the software program toimplement a baseband processing function.

For example, in this application, the antenna that has receiving andsending functions and the control circuit may be considered as atransceiver unit 601 of the terminal device 600, and the processorhaving a processing function may be considered as a processing unit 602of the terminal device 600. As shown in FIG. 6(a), the terminal device600 includes the transceiver unit 601 and the processing unit 602. Thetransceiver unit may also be referred to as a transceiver, atransceiver, a transceiver apparatus, or the like. Optionally, acomponent that is in the transceiver unit 601 and that is configured toimplement a receiving function may be considered as a receiving unit,and a component that is in the transceiver unit 601 and that isconfigured to implement a sending function may be considered as asending unit, in other words, the transceiver unit 601 includes thereceiving unit and the sending unit. For example, the receiving unit mayalso be referred to as a receiver, a receiver, a receiver circuit, orthe like, and the sending unit may be referred to as a transmitter, atransmitter, a transmit circuit, or the like.

On a downlink, a downlink signal (including data and/or controlinformation) sent by a network device is received by using the antenna.On an uplink, an uplink signal (including data and/or controlinformation) is sent to the network device by using the antenna. In theprocessor, service data and a signaling message are processed, and theseunits perform processing according to a radio access technology (such asaccess technologies in LTE, NR, and other evolved systems) used in aradio access network. The processor is further configured to control andmanage an action of the terminal device, and is configured to performprocessing performed by the terminal device in the foregoing embodiment.The processor is further configured to support the terminal device inperforming processing procedures described in FIG. 3(a), FIG. 3(b), andFIG. 4 and performed by the terminal device.

It may be understood that FIG. 6(a) shows only a simplified design ofthe terminal device. In actual application, the terminal device mayinclude any quantity of antennas, memories, processors, and the like,and all terminal devices that can implement this application fall withinthe protection scope of this application.

Specifically, in this application, for example, the transceiver unit isreferred to as a transceiver, and the processing unit is referred to asa processor. In this case, the transceiver and the processor in theterminal device 600 may be specifically configured to:

The transceiver is configured to receive a first RRC configuration of asecondary network device from the secondary network device.

The transceiver is further configured to send first indicationinformation to a primary network device, where the first indicationinformation is used to indicate that the first RRC configuration fails.

Optionally, the transceiver is further configured to send a firstmessage to the primary network device, where the first message includesthe first indication information.

Optionally, if a first unit of the terminal device receives secondindication information sent by a second unit of the terminal device, thetransceiver is further configured to send the first indicationinformation to the primary network device, where the second indicationinformation is used to indicate that the first RRC configurationreceived from the secondary network device fails, the first unit isconfigured to control an RRC connection between the primary networkdevice and the terminal device, and the second unit is configured tocontrol an RRC connection between the secondary network device and theterminal device.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

Optionally, the transceiver is further configured to receive a new RRCconfiguration from the secondary network device.

The transceiver and the processor in the terminal device 600 may befurther specifically configured to.

The transceiver is configured to receive a second RRC configuration of asecondary network device from a primary network device.

If the second RRC configuration fails, the transceiver is furtherconfigured to send a second message to the primary network device, wherethe second message is used to request RRC connection reestablishment.

Optionally, the second message includes third indication information,and the third indication information is used to indicate that the secondRRC configuration fails.

Optionally, if a first unit of the terminal device receives fourthindication information sent by a second unit of the terminal device, thetransceiver is further configured to send the second message to theprimary network device, where the fourth indication information is usedto indicate that the second RRC configuration received from the primarynetwork device fails, the first unit is configured to control an RRCconnection between the primary network device and the terminal device,and the second unit is configured to control an RRC connection betweenthe secondary network device and the terminal device.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

Optionally, the transceiver is further configured to receive a third RRCconfiguration of the primary network device from the primary networkdevice.

If the third RRC configuration fails, the processor performs at leastone of the following actions: stopping executing the second RRCconfiguration, releasing the second RRC configuration, and suspending aradio bearer of the secondary network device.

Optionally, if the second unit receives fifth indication informationsent by the first unit, the processor performs at least one of theforegoing actions, where the fifth indication information is used toindicate that the third RRC configuration fails.

FIG. 6(b) is a schematic diagram of another terminal device according tothis application, and the terminal device may be configured to performan operation performed by the terminal device in any one of theforegoing embodiments. A processor may include a circuit used foraudio/video and logical functions of the terminal device. For example,the processor may include a digital signal processor device, amicroprocessor device, an analog-to-digital converter, adigital-to-analog converter, and the like. Control and signal processingfunctions of a mobile device may be allocated between these devicesbased on respective capabilities of the devices. The processor mayfurther include an internal voice coder (VC), an internal data modem(DM), and the like. In addition, the processor may include functions foroperating one or more software programs, and the software programs maybe stored in a memory. Usually, the processor and the stored softwareinstruction may be configured to enable the terminal device to performan action. For example, the processor can operate a connection program.

The terminal device may further include a user interface. The userinterface may include, for example, a headset or loudspeaker, amicrophone, an output apparatus (for example, a display), and an inputapparatus. The user interface may be operationally coupled to theprocessor. In this case, the processor may include a user interfacecircuit, configured to control at least some functions of one or moreelements (for example, the loudspeaker, the microphone, and the display)of the user interface. The processor and/or the user interface circuitincluded in the processor may be configured to control one or morefunctions of the one or more elements of the user interface by using acomputer program instruction (for example, software and/or firmware)stored in a memory accessible to the processor. Although not shown, theterminal device may include a battery configured to supply power tovarious circuits related to the mobile device. The circuit is, forexample, a circuit that provides mechanical vibration as detectableoutput. The input apparatus may include a device that allows theapparatus to receive data, such as a keypad, a touch display, ajoystick, and/or at least one other input device.

The terminal device may further include one or more connection circuitmodules configured to share and/or obtain data. For example, theterminal device may include a short-range radio frequency (RF)transceiver and/or detector, to share data with an electronic deviceand/or obtain data from an electronic device based on an RF technology.The terminal device may include other short-range transceivers, such asan infrared (IR) transceiver, a Bluetooth transceiver, and a wirelessuniversal serial bus (USB) transceiver. The Bluetooth transceiver canperform an operation based on a low-power or ultra-low-power Bluetoothtechnology. In this case, the terminal device, more specifically, theshort-range transceiver, can send data to and/or receive data from anelectronic device near the apparatus (for example, within 10 meters).Although not shown, the terminal device can send data to and/or receivedata from the electronic device based on various wireless networkingtechnologies, and these technologies include: Wi-Fi, Wi-Fi low powerconsumption, and WLAN technologies such as an IEEE 802.11 technology, anIEEE 802.15 technology, and an IEEE 802.16 technology.

The terminal device may include a memory that can store an informationelement related to a mobile user, such as a subscriber identity module(SIM). In addition to the SIM, the apparatus may further include anotherremovable and/or fixed memory. The terminal device may include atransitory memory and/or a non-transitory memory. For example, thetransitory memory may include a random access memory RAM, and the RAMincludes a dynamic RAM and/or a static RAM, an on-chip and/or off-chipbuffer, and the like. The non-transitory memory may be embedded and/orremovable. The non-transitory memory may include, for example, aread-only memory, a flash memory, a magnetic storage device such as ahard disk, a floppy disk drive, or a magnetic tape, an optical discdrive and/or a medium, a non-transitory random access memory (NVRAM),and the like. Similar to the transitory memory, the non-transitorymemory may include a buffer area used for temporary storage of data. Atleast a part of the transitory memory and/or the non-transitory memorymay be embedded into the processor. The memory may store one or moresoftware programs, instructions, information blocks, data, and the like.The memory may be used by the terminal device to perform a function of amobile terminal. For example, the memory may include an identifier thatcan uniquely identify the terminal device, such as an internationalmobile equipment identity (IMEI) code.

Based on a same concept, an embodiment of this application furtherprovides an apparatus 700. The apparatus 700 may be a network device, ormay be a terminal device. As shown in FIG. 7 , the apparatus 700includes at least a processor 701 and a memory 702, may further includea transceiver 703, and may further include a bus 704.

The processor 701, the memory 702, and the transceiver 703 are allconnected through the bus 704.

The memory 702 is configured to store a computer execution instruction.

The processor 701 is configured to execute the computer executioninstruction stored in the memory 702.

When the apparatus 700 is a network device, the processor 701 executesthe computer execution instruction stored in the memory 702, so that theapparatus 700 performs a step performed by the primary network device inany one of the foregoing failure processing methods, or a functionalunit corresponding to the step is deployed for the primary networkdevice; or the apparatus 700 performs a step performed by the firstprimary network device in the foregoing handover method, or a functionalunit corresponding to the step is deployed for the first primary networkdevice.

When the apparatus 700 is a terminal device, the processor 701 executesthe computer execution instruction stored in the memory 702, so that theapparatus 700 performs a step performed by the terminal device in anyone of the foregoing failure processing methods or the handover methodprovided in the embodiments of this application, or a functional unitcorresponding to the step is deployed for the terminal device.

The processor 701 may include processors 701 of different types, or mayinclude processors 701 of a same type. The processor 701 may be any oneof the following devices having a computing and processing capability,such as a central processing unit (CPU), an ARM processor (English fullname of ARM: Advanced RISC Machines, English full name of RISC: ReducedInstruction Set Computing), a field programmable gate array (FPGA), anda dedicated processor. In an optional implementation, the processor 701may be integrated as a many-core processor.

The memory 702 may be any one or any combination of the followingstorage media, such as a random access memory (RAM), a read-only memory(ROM), a non-transitory memory (NVM), a solid state drive (SSD), amechanical hard disk, a magnetic disk, and a disk array.

The transceiver 703 is used by the apparatus 700 to exchange data withanother device. For example, if the apparatus 700 is a network device,the network device may perform the method performed by the networkdevice in any one of the foregoing embodiments. The network deviceexchanges data with a terminal device by using the transceiver 703. Ifthe apparatus 700 is a terminal device, the terminal may perform themethod performed by the terminal device in any one of the foregoingembodiments. The terminal device exchanges data with a network device byusing the transceiver 703. The transceiver 703 may be any one or anycombination of the following devices having a network access function,such as a network interface (such as an Ethernet interface) and awireless network interface card.

The bus 704 may include an address bus, a data bus, a control bus, andthe like. For ease of representation, the bus is represented by using athick line in FIG. 7 . The bus 704 may be any one or any combination ofthe following components for wired data transmission: an industrystandard architecture (ISA) bus, a peripheral component interconnect(PCI) bus, an extended industry standard architecture (EISA) bus, andthe like.

An embodiment of this application provides a computer-readable storagemedium, where the computer-readable storage medium stores a computerexecution instruction. A processor of a terminal device executes thecomputer execution instruction, so that the terminal device performs astep performed by the terminal device in the foregoing failureprocessing methods and the handover method provided in this application,or a functional unit corresponding to the step is deployed for theterminal device.

An embodiment of this application provides a computer-readable storagemedium, where the computer-readable storage medium stores a computerexecution instruction. A processor of a network device executes thecomputer execution instruction, so that the network device performs astep performed by the primary network device in the foregoing failureprocessing methods provided in this application, or a functional unitcorresponding to the step is deployed for the network device; or thenetwork device performs a step performed by the first primary networkdevice in the foregoing handover method provided in this application, ora functional unit corresponding to the step is deployed for the networkdevice.

An embodiment of this application provides a computer program product.The computer program product includes a computer execution instruction,and the computer execution instruction is stored in a computer-readablestorage medium. A processor of a terminal device may read the computerexecution instruction from the computer-readable storage medium. Theprocessor executes the computer execution instruction, so that theterminal device performs a step performed by the terminal device in theforegoing methods provided in the embodiments of this application, or afunctional unit corresponding to the step is deployed for the terminaldevice.

An embodiment of this application provides a computer program product.The computer program product includes a computer execution instruction,and the computer execution instruction is stored in a computer-readablestorage medium. A processor of a network device may read the computerexecution instruction from the computer-readable storage medium. Theprocessor executes the computer execution instruction, so that thenetwork device performs a step performed by the primary network devicein the foregoing failure processing methods provided in the embodimentsof this application, or a functional unit corresponding to the step isdeployed for the network device; or the network device performs a stepperformed by the first primary network device in the foregoing handovermethod provided in the embodiments of this application, or a functionalunit corresponding to the step is deployed for the network device.

This application further provides a chip system. The chip systemincludes a processor, configured to support a terminal device inimplementing functions in the foregoing aspects, for example,generating, receiving, or processing data and/or information in theforegoing methods. In a possible design, the chip system furtherincludes a memory. The memory may be configured to store a programinstruction and data that are necessary for the terminal device. Thechip system may include a chip, or may include a chip and anotherdiscrete device.

This application further provides a chip system. The chip systemincludes a processor, configured to support a network device inimplementing functions in the foregoing aspects, for example,generating, receiving, or processing data and/or information in theforegoing methods. In a possible design, the chip system furtherincludes a memory. The memory is configured to store a programinstruction and data that are necessary for the data receiving device.The chip system may include a chip, or may include a chip and anotherdiscrete device.

Based on a same concept, this application further provides a terminaldevice 800. As shown in FIG. 8 , the terminal device 800 includes aprocessing unit 801 and a transceiver unit 802, and may be configured toperform the method performed by the terminal device in any one of theforegoing embodiments. Optionally, the processing unit 801 and thetransceiver unit 802 are configured to.

The transceiver unit 802 is configured to receive a first RRCconfiguration of a secondary network device from the secondary networkdevice.

The transceiver unit 802 is further configured to send first indicationinformation to a primary network device, where the first indicationinformation is used to indicate that the first RRC configuration fails.

Optionally, the transceiver unit 802 is further configured to send afirst message to the primary network device, where the first messageincludes the first indication information.

Optionally, if a first unit of the terminal device receives secondindication information sent by a second unit of the terminal device, thetransceiver unit 802 is further configured to send the first indicationinformation to the primary network device, where the second indicationinformation is used to indicate that the first RRC configurationreceived from the secondary network device fails, the first unit isconfigured to control an RRC connection between the primary networkdevice and the terminal device, and the second unit is configured tocontrol an RRC connection between the secondary network device and theterminal device.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

Optionally, the transceiver unit 802 is further configured to receive anew RRC configuration from the secondary network device.

The processing unit 801 and the transceiver unit 802 are furtherconfigured to:

The transceiver unit 802 is configured to receive a second RRCconfiguration of a secondary network device from a primary networkdevice.

If the second RRC configuration fails, the transceiver unit 802 isfurther configured to send a second message to the primary networkdevice, where the second message is used to request RRC connectionreestablishment.

Optionally, the second message includes third indication information,and the third indication information is used to indicate that the secondRRC configuration fails.

Optionally, if a first unit of the terminal device receives fourthindication information sent by a second unit of the terminal device, thetransceiver unit 802 is further configured to send the second message tothe primary network device, where the fourth indication information isused to indicate that the second RRC configuration received from theprimary network device fails, the first unit is configured to control anRRC connection between the primary network device and the terminaldevice, and the second unit is configured to control an RRC connectionbetween the secondary network device and the terminal device.

Optionally, the first unit is a first RRC entity, and the second unit isa second RRC entity.

Optionally, the transceiver unit 802 is further configured to receive athird RRC configuration of the primary network device from the primarynetwork device.

If the third RRC configuration fails, the processing unit 801 performsat least one of the following actions: stopping executing the second RRCconfiguration, releasing the second RRC configuration, and suspending aradio bearer of the secondary network device.

Optionally, if the second unit receives fifth indication informationsent by the first unit, the processing unit 801 performs at least one ofthe following actions, where the fifth indication information is used toindicate that the third RRC configuration fails.

Based on a same concept, this application further provides a networkdevice 900. As shown in FIG. 9 , the network device 900 includes aprocessing unit 901 and a transceiver unit 902, and may be configured toperform the method performed by the primary network device in theforegoing failure processing methods, or may be configured to performthe method performed by the first primary network device in theforegoing handover method. Optionally, the processing unit 901 and thetransceiver unit 902 are configured to:

The transceiver unit 902 is configured to receive first indicationinformation from a terminal device, where the first indicationinformation is used to indicate that a first RRC configuration of asecondary network device fails, and the first RRC configuration isreceived by the terminal device from the secondary network device.

The transceiver unit 902 is further configured to send a first requestmessage to the secondary network device, where the first request messageis used to request the secondary network device to update an RRCconfiguration or request to release the secondary network device.

Optionally, the first request message includes the first indicationinformation.

Optionally, the processing unit 901 and the transceiver unit 902 arefurther configured to:

If a second RRC configuration of a secondary network device fails, thetransceiver unit 902 is configured to receive a second message from aterminal device, where the second message is used to indicate RRCconnection reestablishment, and the second RRC configuration is receivedby the terminal device from the primary network device.

The transceiver unit 902 is further configured to initiate the RRCconnection reestablishment to the terminal device.

Optionally, the second message includes third indication information,and the third indication information is used to indicate that the secondRRC configuration fails.

Optionally, the processing unit 901 and the transceiver unit 902 arefurther configured to.

The transceiver unit 902 is configured to send a third message to asecond primary network device, where the third message is used torequest handover, and the third message includes a capabilitycoordination result between the first primary network device and thesecondary network device.

The transceiver unit 902 is further configured to receive aconfiguration of the second primary network device that is sent by thesecond primary network device, where the configuration of the secondprimary network device is associated with the capability coordinationresult.

Optionally, the capability coordination result includes a size of alayer 2 buffer that can be used by the first primary network deviceand/or a band combination that can be used by the first primary networkdevice.

Optionally, the transceiver unit 902 is further configured to receive aconfiguration of the secondary network device.

The transceiver unit 902 is further configured to send the configurationof the second primary network device and the configuration of thesecondary network device to a terminal device.

Optionally, the transceiver unit 902 is further configured to receivethe configuration of the secondary network device from the secondprimary network device.

Optionally, if the configuration of the secondary network device fails,the transceiver unit 902 is further configured to receive a fourthmessage from the terminal device, where the fourth message is used toindicate RRC connection reestablishment.

Based on a same concept, as shown in FIG. 10 , this application furtherprovides a communications device 1000. The communications device 1000may be a terminal device, a baseband chip, or the like, and includes afirst unit 1001 and a second unit 1002. For details, refer to FIG. 2(a)and FIG. 2(b). The first unit 1001 and the second unit 1002 may beconfigured to respectively perform functions performed by the first unit1001 and the second unit 1002 in the foregoing failure processingmethods. For details, refer to the foregoing description.

For example, the following describes some functions of the first unit1001 and the second unit 1002. The first unit 1001 is configured tocontrol an RRC connection between a primary network device and theterminal device, and the second unit 1002 is configured to control anRRC connection between a secondary network device and the terminaldevice.

Optionally, the second unit 1002 generates second indication informationif the second unit 1002 determines that a first RRC configuration of thesecondary network device that is received by the terminal device fromthe secondary network device fails, where the second indicationinformation is used to indicate that the first RRC configuration fails.The second unit 1002 sends the second indication information to thefirst unit 1001.

Optionally, the second unit 1002 generates fourth indication informationif the second unit 1002 determines that a second RRC configuration ofthe secondary network device that is received by the terminal devicefrom the primary network device fails, where the fourth indicationinformation is used to indicate that the second RRC configuration fails.The second unit 1002 sends the fourth indication information to thefirst unit 1001.

Optionally, the first unit 1001 generates fifth indication informationif the first unit 1001 determines that a third RRC configuration of thesecondary network device that is received by the terminal device fromthe primary network device fails, where the fifth indication informationis used to indicate that the third RRC configuration fails. The firstunit 1001 sends the fifth indication information to the second unit1002.

Optionally, the second unit sends failure indication information to thefirst unit, where the failure indication information is used to indicatethat a link between the terminal device and the secondary network devicefails; and the first unit receives the failure indication information.Optionally, the failure indication information is specifically used toindicate any one of the following cases: a timer expires, a quantity ofretransmission times exceeds a maximum quantity of times, random accessfails, a secondary-cell group change fails, a key fails, a check fails,integrity protection fails, a secondary network configuration receivedfrom the secondary network device fails, and a secondary networkconfiguration received from a primary network device fails.

When the failure indication information is used to indicate that thesecondary network configuration received from the secondary networkdevice fails, the failure indication information is the secondindication information described above.

When the failure indication information is used to indicate that thesecondary network configuration received from the primary network devicefails, the failure indication information is the fourth indicationinformation described above.

Optionally, the first unit 1001 is a first RRC entity, and the secondunit 1002 is a second RRC entity.

All or some of the foregoing embodiments may be implemented by usingsoftware, hardware, firmware, or any combination thereof. When softwareis used to implement the embodiments, the embodiments may be implementedcompletely or partially in a form of a computer program product. Thecomputer program product includes one or more computer instructions.When the computer program instructions are loaded and executed on thecomputer, all or some of the procedures or functions in this applicationare generated. The computer may be a general-purpose computer, adedicated computer, a computer network, or other programmableapparatuses. The computer instructions may be stored in acomputer-readable storage medium or may be transmitted from acomputer-readable storage medium to another computer-readable storagemedium. For example, the computer instructions may be transmitted from awebsite, computer, server, or data center to another website, computer,server, or data center in a wired (for example, a coaxial cable, anoptical fiber, or a digital subscriber line (DSL)) or wireless (forexample, infrared, radio, or microwave) manner. The computer-readablestorage medium may be any usable medium accessible by a computer, or adata storage device, such as a server or a data center, integrating oneor more usable media. The usable medium may be a magnetic medium (forexample, a floppy disk, a hard disk, or a magnetic tape), an opticalmedium (for example, a DVD), a semiconductor medium (for example, asolid state disk (SSD)), or the like.

A person skilled in the art can further understand that, the variousillustrative logical blocks and the steps (step) listed in thisapplication may be implemented through electronic hardware, computersoftware, or a combination of the two. Whether the functions areimplemented by using hardware or software depends on particularapplications and a design requirement of an entire system. A personskilled in the art may use various methods to implement the describedfunctions for each particular application, but it should not beconsidered that the implementation goes beyond the protection scope ofthis application.

Various illustrative logic units and circuits described in thisapplication may implement or operate the described functions by using ageneral-purpose processor, a digital signal processor, anapplication-specific integrated circuit (ASIC), a field programmablegate array (FPGA) or another programmable logic apparatus, a discretegate or transistor logic, a discrete hardware component, or a design ofany combination of the foregoing. The general-purpose processor may be amicroprocessor. Optionally, the general-purpose processor may also beany conventional processor, controller, microcontroller, or statemachine. The processor may alternatively be implemented by a combinationof computing apparatuses, such as a digital signal processor and amicroprocessor, a plurality of microprocessors, one or moremicroprocessors together with a digital signal processor core, or anyother similar configuration.

Steps of the methods or algorithms described in this application may bedirectly embedded into hardware, a software unit executed by theprocessor, or a combination thereof. The software unit may be stored ina random access memory (RAM), a flash memory, a read-only memory (ROM),an erasable programmable read only memory (, EPROM), a register, a harddisk, a removable disk, a compact disc read-only memory (CD-ROM), or anyother form of storage medium in the art. For example, the storage mediummay be connected to the processor, so that the processor may readinformation from the storage medium and write information to the storagemedium. Alternatively, the storage medium may be integrated into theprocessor. The processor and the storage medium may be disposed in anASIC, and the ASIC may be disposed in a terminal device or a networkdevice. Optionally, the processor and the storage medium may be disposedin different components of the terminal device or the network device.

In one or more example designs, the functions described in thisapplication may be implemented by using hardware, software, firmware, orany combination thereof. If the functions are implemented by usingsoftware, the functions may be stored in a computer-readable medium orare transmitted to the computer-readable medium in a form of one or moreinstructions or code. The computer-readable medium includes a computerstorage medium and a communications medium that enables a computerprogram to move from one place to another place. The storage medium maybe an available medium that can be accessed by any general-purpose orspecial computer. For example, such a computer-readable medium mayinclude but is not limited to a RAM, a ROM, an EEPROM, a CD-ROM oranother optical disc storage, a disk storage or another magnetic storageapparatus, or any other medium that may be used to bear or store programcode, where the program code is in a form of an instruction or a datastructure or in a form that can be read by a general-purpose or specialcomputer or by a general-purpose or special processor. In addition, anyconnection may be appropriately defined as a computer-readable medium.For example, if software is transmitted from a website, a server, oranother remote resource by using a coaxial cable, an optical fibercable, a twisted pair, a digital subscriber line (DSL) or in a wirelessmanner, such as infrared, radio, or microwave, the software is includedin a defined computer-readable medium. The disc and the disk include acompressed disk, a laser disk, an optical disc, a digital versatile disc(DVD), a floppy disk, and a Blu-ray disc. The disk generally copies databy a magnetic means, and the disc generally copies data optically by alaser means. The foregoing combination may also be included in thecomputer-readable medium.

A person skilled in the art should be aware that in one or more of theforegoing examples, the functions described in this application may beimplemented by using hardware, software, firmware, or any combinationthereof. When the functions are implemented by software, these functionsmay be stored in a computer-readable medium or transmitted as one ormore instructions or code in the computer-readable medium. Thecomputer-readable medium includes a computer storage medium and acommunications medium, where the communications medium includes anymedium that enables a computer program to be transmitted from one placeto another. The storage medium may be any available medium accessible toa general-purpose or dedicated computer.

The objectives, technical solutions, and beneficial effects of thisapplication are further described in detail in the foregoing specificimplementations. It should be understood that the foregoing descriptionsare merely specific implementations of this application, but are notintended to limit the protection scope of this application. Anymodification, equivalent replacement, or improvement made based on thetechnical solutions of this application shall fall within the protectionscope of this application. The foregoing descriptions of thisspecification in this application may enable a person skilled in the artto use or implement the content of this application. It should beconsidered that any modification made based on the disclosed content isobvious in the art. The basic principles described in this applicationmay be applied to other variants without departing from the essence andscope of this application. Therefore, the content disclosed in thisapplication is not limited to the described embodiments and designs, butmay be further extended to a maximum scope that is consistent with theprinciples of this application and new features disclosed in thisapplication.

What is claimed is:
 1. An apparatus comprising: one or more processors;and a memory having instructions stored thereon for execution by the oneor more processors to cause the apparatus to perform operationscomprising: receiving a radio resource control (RRC) configuration of asecondary network device; and if the RRC configuration of the secondarynetwork device is from the secondary network device and the RRCconfiguration fails, sending, to a primary network device, firstindication information for indicating a configuration failure of the RRCconfiguration.
 2. The apparatus according to claim 1, wherein sendingthe first indication information to the primary network devicecomprises: sending a first message to the primary network device,wherein the first message comprises the first indication information. 3.The apparatus according to claim 1, wherein the operations furthercomprising: if the RRC configuration of the secondary network device isfrom the primary network device and the RRC configuration fails,sending, to the primary network device, a second message for requestingRRC connection reestablishment.
 4. The apparatus according to claim 3,wherein the second message comprises second indication information forindicating a configuration failure of the RRC configuration.
 5. Theapparatus according to claim 3, wherein sending the second messagecomprises: if a first RRC entity of the apparatus receives thirdindication information from a second RRC entity of the apparatus,sending the second message to the primary network device, wherein thethird indication information indicates a configuration failure of theRRC configuration received from the primary network device, the firstRRC entity controls a RRC connection between the primary network deviceand the apparatus, and the second RRC entity controls a RRC connectionbetween the secondary network device and the apparatus.
 6. An apparatuscomprising: one or more processors; and a memory having instructionsstored thereon for execution by the one or more processors to cause theapparatus to perform operations comprising: if a radio resource control(RRC) configuration of a secondary network device is received by aterminal device from the secondary network device, receiving, from theterminal device, first indication information for indicating aconfiguration failure of the RRC configuration; and sending, to thesecondary network device, a request for updating the RRC configurationor releasing the secondary network device.
 7. The apparatus according toclaim 6, wherein the first indication information is comprised in therequest.
 8. The apparatus according to claim 6, wherein receiving thefirst indication information from the terminal device comprises:receiving a first message from the terminal device, wherein the firstmessage comprises the first indication information.
 9. The apparatusaccording to claim 6, wherein the operations further comprising: if theRRC configuration of the secondary network device is received by theterminal device from the apparatus, receiving, from the terminal device,a second message for requesting RRC connection reestablishment.
 10. Theapparatus according to claim 9, wherein the second message comprisessecond indication information for indicating a configuration failure ofthe RRC configuration.
 11. The apparatus according to claim 9, whereinthe operations further comprising: sending, to the terminal device,third message for reestablishing a signaling radio bearer (SRB).
 12. Amethod comprising: if a radio resource control (RRC) configuration of asecondary network device is received by a terminal device from thesecondary network device, receiving, by a primary network device fromthe terminal device, first indication information for indicating aconfiguration failure of the RRC configuration; and sending, by theprimary network device to the secondary network device, a request forupdating the RRC configuration or releasing the secondary networkdevice.
 13. The method according to claim 12, wherein the firstindication information is comprised in the request.
 14. The methodaccording to claim 12, wherein receiving, by the primary network devicefrom the terminal device, the first indication information comprises:receiving, by the primary network device from the terminal device, afirst message, wherein the first message comprises the first indicationinformation.
 15. The method according to claim 12, further comprising:if the RRC configuration of the secondary network device is received bythe terminal device from the primary network device, receiving, by theprimary network device from the terminal device, a second message forrequesting RRC connection reestablishment.
 16. The method according toclaim 15, wherein the second message comprises second indicationinformation for indicating a configuration failure of the RRCconfiguration.
 17. The method according to claim 15, further comprising:sending, by the primary network device to the terminal device, thirdmessage for reestablishing a signaling radio bearer (SRB).
 18. A methodcomprising: receiving, by a terminal device, a radio resource control(RRC) configuration of a secondary network device; if the RRCconfiguration of the secondary network device is from the secondarynetwork device and the RRC configuration fails, sending, by the terminaldevice to a primary network device, first indication information forindicating a configuration failure of the RRC configuration; receiving,by the primary network device, the first indication information; andsending, by the primary network device to the secondary network device,a request for updating the RRC configuration or releasing the secondarynetwork device.
 19. The method according to claim 18, wherein the firstindication information is comprised in the request.
 20. The methodaccording to claim 18, further comprising: if the RRC configuration ofthe secondary network device is from the primary network device and theRRC configuration fails, sending, by the terminal device to the primarynetwork device, a second message for requesting RRC connectionreestablishment; and receiving, by the primary network device, thesecond message.